The check engine light (CEL) is designed to keep your Mercedes’ engine safe. It informs the driver of an issue that is affecting the performance of the engine, allowing the driver to take immediate action to prevent further damage. Let’s take a look at some of the reasons why the check engine light can become illuminated.
1. Loose Gas Cap
This problem is largely caused by the driver being distracted when filling up at the pumps. A loose gas cap can cause the check engine light to illuminate. This is because a loose fuel cap prevents a tight seal from being created, meaning that vapors can escape, fuel wastage is increased, and engine performance lowers. Always check that you have secured your gas cap before departing from the gas station. If the cap is damaged, you may think that you have secured it tightly but cracks and damage to the thread of the cap can prevent it from tightening correctly. If this is the case, then replace the gas cap as soon as possible.
2. Dirty O2 Sensor
The O2 sensor can become coated by ash and other sooty deposits found in burned fuel. This can affect the performance of the sensor, which is required to test the oxygen levels that are present in the exhaust fumes. A contaminated O2 sensor will dramatically increase emissions levels, impact your fuel efficiency, and will trigger the check engine light, due to detrimentally-affecting performance levels.
3. Catalytic Converter
A CEL triggered by the catalytic converter is a worst-case scenario and can indicate a clogged or completely failed unit. The catalytic converter is essential for making your emissions safe, and without one, your Mercedes is harmful to you and those around you, along with poisoning the environment.
4. Mass Airflow Sensor
The MAF sensor is needed to ensure the correct air and fuel ratio is used in the combustion cycle. It monitors the air flow inside the engine, allowing the onboard computer to select the correct amount of fuel to match it. When the MAF sensor becomes dirty or stops working, performance levels will drop, which will cause the onboard computer to trigger the check engine light.
5. Spark Plugs
Worn out spark plugs are a common cause of CEL illumination. Spark plugs are worn out by the high voltage spark that each set passes between themselves constantly as you drive. The spark chips away at the surface of the plug. Over time, it widens the gap to a point where consistent sparking cannot be maintained, resulting in misfires.
6. Aftermarket Alarm
A badly-installed aftermarket alarm can jeopardize your Mercedes’ entire electrical system. Most commonly, it will drain the battery, resulting in the illumination of the battery warning light and the check engine light.
7. Vacuum System Leaks
The vacuum system helps to reduce the amount of emissions that your Mercedes produces. It also acts as a brake booster. When your Mercedes has a vacuum leak, you’ll notice engine surges when idle and a higher RPM than normal. The CEL will likely illuminate in response to this.
8. EGR Valve Problems
The EGR valve also works to make your emissions as safe as possible. It reduces how much nitrogen oxide is released. When this develops faults or becomes clogged, however, it will trigger the illumination of the check engine light.
9. Dead Battery
The battery is essential to starting and powering your Mercedes’ various electrical systems. When the battery has low change or is completely dead, the CEL will illuminate along with the battery warning light.
10. False Error
Lastly, the on-board computer may have a fault of its own and might accidentally trigger the CEL, despite there being no issue. This is known as a false error code. This will require diagnostic equipment to reset it. However, until a false code is confirmed, it needs to be deemed as a genuine engine issue.
The Benz Shop
Arizonians driving in and around Phoenix, AZ can rely on the excellent service our team offers at The Benz Shop. When you need us, we’ll be there to help. For correct repairs and reputable service, don’t settle for anything less than The Benz Shop for all your maintenance and repair needs. Call us today to schedule an appointment.